"Good" (well-extracted) coffee is still relatively good when warm, especially compared to "bad" (over-extracted, or under-extracted) coffee. That said, many believe that the optimal temperature for serving coffee is 50-60 degrees celsius (122-140 degrees fahrenheit).
Yes, but the test was at 22°C, which I wouldn’t consider warm. And it’s too cold for the differences to be even perceptible well, making the test flawed. Disregarding the fact that it’s also much colder than people use to drink coffee, making it even harder to distinguish for non-experts.